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W. TAYLOR AND F. W. PRESTON. APPARATUS FOR PREPARING LENSES AND THE LIKEFOR GRINDING AND POLISHING.

' APPLICATION FILED FEB. II, I920. RENEWED SEPT. 23, 1920. 1,358,677.

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w. TAYLOR AND F. w. PRESTON.

APPARATUS FOR PREPARING LENSES AND THE LIKE FOR GRINDING AND POLISHING.

APPLICATION FILED FEB. I I, 1 920- RENEWED SEPT. 23, 1920. 1,358,677;

UNITED STATES PATENT OFFICE.

\VILLIAM TAYLOR AND FRANCIS WILLIAM PBESTGN, 0F LEICESTER, ENGLAND.

APPARATUS FOR PREPARING LENSES THE LIKE FOR GRINDING AND POLISHING.

Specification of Letters Patent.

Patented Nov. 9, mac.

Original application filed October 17, 1919, Serial No. 331,435. Dividedand. this application filed Feb.

ruary 11, 1920, Serial No. 357,865. Renewed September 23, 1920. SerialNo. 412,415.

T 0 all whom it may, concern:

Be it known that we, \VILLIAM Terror,

engineer, and FRANCIS VVILLrAir Pnns'ro v, engineer, both of StoughtonStreet Works, Leicester, 1n the county of Leicester, England, haveinvented certain new and useful Improvements in Apparatus for PreparingLenses and the like for Grinding and Pol ishing, of which the followingis-a specification.

This invention relates to improved apparatus for use in mounting lensesand the like in preparation for the grinding and polishing operations,and it has for its principal objects to provide appliances with whichsuch mounting may be accomplished more expeditiously than heretofore,and with less risk of springing and distorting the lenses in themounting. 1

It is usual, in grinding and polishing lenses, to attach each lens to aholder by means of a material such as pitch interveiling between thelens and the holder. A number of lenses are frequently held in this wayto one holder, so that their surfaces conform to one general surface andmay be ground and polished together. Such a group is termed a block.

The customary practice followed in carrying out the operation is liableto give rise to various defects in the finished lenses,.the principaldefect being due to the fact that the lenses, (apparently through localshrinkage and expansion of the pitch) become strained in such mannerthat although, so long as the lenses remain on the holder and up to thecompletion of the polishing process, their surfaces may have a form'which is satisfactory, nevertheless when finally removed from'the pitchthe lenses, being released from strain, become distortcd.

Systematic investigation of this subject has shown us that, in order toreduce such distortion, the pitch backing on each lens should be placedsymmetrically about the axis of the lens; and the backings on allsimilar lenses in a block should be uniform in size and shape.

vVe further find that, in the case of some lenses, we can reduce thedistortion by forming the pitch backing hollow at the center or heart ofthe mass of pitch The method for mounting lenses and the like which wehave invented and the apparatus for placing the lenses in properposition upon the holder are described and claimed in our applicationfor Letters Patent of the United States, Serial No. 381,436, filedOctober 17, 1919, of which the present application is a division. Thepresent application is directed particularly to apparatus for use inapplying the binder to the lenses.

In the accompanying drawings, Figures '1 and 2 illustrate, in sideelevation and plan respectively, one form of apparatus for heating thepitch, for delivering it to lenses in molds, for closing the molds, andfor coating the surface of each lens with tacky previous to theapplication of the pitch. Fig. 3 is a side elevation, partly in axialsection, of one of the molds seen in Figs. 1 and 2 (but drawn to alarger scale) together with the plunger which constitutes the closurefor the mold; a lei-convex lens being shown in position in the mold.Fig. 4 is a partly sectional side view of a biconvex lens with themolded mass of pitch adherent to it. Fig. 5 is a side elevation of aconvenient form 0 tacky spray-nozzle.

11 (Figs. 1 and 2) is the hollow body or container of a mixing machine,of well known type, which we find suitable for use in heating andconditioning the pitch; the container being provided with a steam jacket12 supplied with steam through a pipe 13, while 1% is a pipe fordraining water of condensation from the jacket. The container 11 has aremovable cover 15 provided with a hopper 16 for the introduction offresh pitch into the container, the hopper. being normally closed by acover 17. A pair of. rotary paddles 18, 18 mounted on shafts 19, 19serve to stir up the pitch with-v in the container 11; the shafts 19, 19being.

geared together and adapted to be continuously driven by suitable means(not shown).

A steam-jacketed pipe 20 leads from the the upper surface of the lens,forms a coaming adapted both to retain the lens in posi-- tion withinthemold'and also to confine the pitch laterally during the moldingoperation. The plunger B which forms the closure for the mold is adaptedto be brought into operative position, after the mold has been tilledwith pitch, by downward move ment in the direction of the common axis ofthe mold, lens and plunger, and, in the example illustrated, comprisesan annular" rim 27 adapted to contact with the upper edge 28 of the cap26 and a central circular projection 29 which, by entering the mass ofpitch bounded by the cap, forms in said mass a central depression 30, sothat the pitch 31 which adheres to the lens 32 when the latter isremoved from the mold, presents in axial volve about a fixed verticalstud 34 and provided at equal intervals with upright pegs 35 (Fig. 2)adapted to enter holes 36 (Fig. 3) in the base portions 23 of theseveral molds; the turntable 33 being rotated stepby-step throughangular intervals corresponding to those separating the pegs F or thispurpose, in the example illustrated, the turntable 33 has'on its lowerside a dependent annular flange 37 in which are formeda series of radialgrooves 38 opening out at both the external and internal peripheriesof'the flange; these grooves, which are spaced apart at angularintervals corresponding to those between the pegs 35, being engaged insuccession by a pair of crank pins 39 (carrying antifriction rollers)which project vertically from a disk 40 fast on the upper end of avertical shaft 11 revolved at a suitable speed by any convenient means(not shown). The'shat't 41 may be continuously driven through frictionalgearing so as to permit of any convenient means (not shown) beingemployed for arresting the rotation of the turntable 33 periodicallyduring the intervals when successive molds are being dealtwith.

As seen in plan view, 2, the turntable 33 is to be understood asintended to be revolved contra-clockwise so as to bring successive moldsA, first, under a spraynozzle 4-2 for delivering tacky on to the uppersurface of each lens 32 in its mold, secondly, under the pitch-deliverynozzle 21, and thirdly under the plunger B which serves as a closure forall. the molds in succession. The tacky may be ejected by any convenientmeans, for example a pneumaticallyoperated device such as is commonlyemployed for spraying paint, varnish or the like.

The plunger B, which is shown in Fig. 1 as detachably fixed on the lowerend oi a vertical spindle 43 so as tobe changeableto suit differentmolds, is actuated by sliding the spindle 43 through a stationary guide44 supported on abracket 45 extending fronr the fixed stud34 about whichthe turntable 33-revolves; the upper end of the spindle 43 beingconnected by a link 46 to'a handlever 47: fulcrumed at A8 to the bracketto. The spindle 43 may be normally retained in the raised position, soas to hold the plunger B clear of the molds A, by means of a coiledspring housed within the guide 4% but not shown in the drawing. As theplunger is depressed by means of the lever 47 until arrested by the rim27 encountering theedge 28 01? the mold-cap 26, the surplus pitchescapes over the edge 28. After the pitch has set to the shape given toit by the mold and plunger, the'plunger is raised and the lens 32 withits adherent mass of pitch can be removed from the mold. The central deression or cavit 30 formed in themass drawing-in of the center of thelens and thus causing distortion. 7

Although we have described the above apparatus as applied tov pitch orthe like substances capable of being softened by heat, it will beobvious that much of our invention is equally applicable wheresubstances areemployed such'as plaster of Paris and other Jcementssometimes used for mounting lenses, which areliable to shrinkage orexpansion during setting in the operation of mounting lenses and thelike.

Having now particularly described and ascertainedthe nature of our saidinvention and in what manner the same is to be performed, we declarethat what we claim is 1. Apparatus for applying a binder to lenses orthe like, comprising a mold, a

support for the lens therein, retaining walls 2. Apparatus for applyinga binder' to lenses or the like, comprising a mold, a sup portwithinsaid mold for the-lens, retaining walls above-said support, a loosefitting closure for said mold, means for filling said mold with a fluidbinder, and means for applying said closure to the mold.

3. Apparatus for applying a binder to lenses or the like, comprising amold having a support for the lens and having an opening at its top,means for introducing a fluid binder into said mold, and a plungeradapted to enter the hole in said mold and to form a central recess inthe binder molded therein.

4. Apparatus for applying a binder to lenses or the like, comprising amovable carrier, a plurality of molds upon said carrier each having asupport for a lens and an opening at the top, means for pouring a fluidbinder into one of said molds, a reciprocating closure adapted to closethe hole in one of said molds, and means for causing a step-by-stepmovement of said carrier so as to bring each mold first under saidpouring means and subsequently in line with said plunger.

5. Apparatus for applying a binder to lenses or the like, comprising a'movable carrier, a plurality of molds upon said carrier each having asupport for a lens and an opening at the top, means for spraying tackyupon a lens in one of said molds, means for pouring a fluid binder intoone of said molds, a reciprocating closure adapted to close the hole inone of said molds, and means for causing a step-by-step movement of saidcarrier so as to bring each mold first under said spraying means andthen under said pouring means and subsequently in line with saidplunger.

6. Apparatus for applying a binder to lenses and the like, comprising abase having means for supporting the edge of the lens, and a capdetachably fastened to said base and arranged to hold the lens inposition upon said base and to provide a chamber in which the binder maybe molded.

7. Apparatus for applying a binder to lenses and the like, comprising abase having an annular shelf to support the periphery of the lens, and acap detachably fastened to said base and having an upwardly taperingconical inner. surface adapted to contact with the periphery of the lensand hold it in position upon said shelf and to form a chamber formolding the binder.

8. Apparatus for applying a backing to a lens, comprising a base havingan annular seat for the lens, a cap detachably fastened to said base andhaving an upwardly taporing inner surface adapted to contact with theperiphery of the lens and hold it in position upon said seat and havingan opening at its top and providing a chamber above the lens for moldingthe backing, and a loose fitting closure for the opening at the top ofsaid cap piece.

9. Apparatus for applying a binder to lenses or the like comprising amold having a chamber of predetermined volume for the reception of thebinder, and means for positioning a lens in predetermined relation tosaid chamber.

10. Apparatus for applying a binder to lenses or the like, comprising amold having an opening, means for introducing a fluid binder into saidmold through said opening, a closure for said mold adapted to be movedinto predetermined relation to said mold so as to force from the moldany surplus binder, and means for positioning a lens in predeterminedrelation tosaid mold.

11. Apparatus for applying a binder to lenses or the like, comprising amold hav ing an opening, means for filling said mold with a fluid binderthrough said opening, a closure adapted to be brought into contact withthe mold at the periphery of said opening so as to force from the moldany surplus binding material and to sever the surplus from the materialremaining in the mold, and means for positioning a lens in predeterminedrelation to said mold.

12. Apparatus for applying a binder to lenses or the like comprising amold having a chamber of predetermined volume for the reception of thebinder, and means for positioning a lens in predetermined relation tosaid chamber by engagement with the periphery and one face of the lens.

13. Apparatus for applying a binder to lenses and the like comprising amold, an annular seat in said mold adapted to support the lens byengagement with the outer portion of one side thereof, retaining wallsabove said seat, and means for filling the space within said walls witha fluid binder.

WILLIAM TAYLOR. FRANCIS WILLIAM PRESTON.

Witnesses THOMAS EDGLEY HUnsoN, ELsIn MADY BENT.

